1. FIELD OF THE INVENTION
The present invention is intended to crack the shells of pine nuts and relates to an improvement in a shell cracking apparatus which has now been on file in the form of a Japanese Patent Application No. 60-10393 as filed by the present Applicant under date of Jan. 22, 1985 (Japanese Patent Unexamined Publication No. 61-171551 dated Aug. 20, 1986).
Hard-shell coated seeds such as, for example, gingko nut, pine nut, or the like are used for cooking after their shells have been taken away and then processed, or are processed into confectionaries or foodstuff for use as "sake and sakana (eatables)" which is thus put on sale. Pine nuts in particular are coated with hard shells, and their seeds contain a large amount of fat and yet are soft. Thus, pine nuts are highly nutritious foodstuff and are considered to increase in their future demand.
2. DESCRIPTION OF THE PRIOR ART
The shell-cracking apparatuses which are disclosed in Japanese Utility Model Examined Publications Nos. 13-16535, 402280, and 27-2679 have hitherto been proposed as shell-cracking means for hard-shell coated seeds. These shell-cracking apparatuses are inefficient and therefore are unsuitable for cracking the shells of a large number of pine nuts. On the other hand, the shell-cracking apparatus which is disclosed in Japanese Utility Model Examined Publication No. 52-17515 has a drawback in that it causes damage to the embryos of the seeds, although it is somewhat higher in the cracking efficiency than the above-mentioned shell-cracking apparatuses.
The shell-cracking apparatus which is now on file in the form of Japanese Patent Application No. 60-10393 has solved the problems of any one of the first-mentioned shell-cracking apparatuses. Namely, it is high in the cracking efficiency and is capable of processing a large number of seeds. This shell-cracking apparatus, however, has structural drawbacks in that the seeds are likely to drop outside a seed discharging cylindrical member without coming into the same, and that the shells and contents of the seeds as cracked are likely to be scattered. This requires assistance by hands in order to make the necessary rearrangements. Thus, the present Applicant has attempted, not only to increase the force of air injection as compared with the shell-cracking apparatus of the pending Japanese Patent Application No. 60-10393, but also to recover the seeds having dropped outside the cylindrical seed-discharging member, to prevent the scattering of the shells and fruits or contents produced due to collision of the seeds against a pad plate, and to speedily discharge the air having impinged upon the pad plate to thereby prevent the blockage of the holes formed in the pad plate, thus to enhance the cracking efficiency.